Metals by Micro-Scale Additive Manufacturing: Comparison of Microstructure and Mechanical Properties

Reiser, Alain; Koch, Lukas; Dunn, Kathleen A.; Matsuura, Toshiki; Iwata, Futoshi; Fogel, Ofer; Kotler, Zvi; Zhou, Nanjia; Charipar, Kristin; Piqué, Alberto; Rohner, Patrik; Poulikakos, Dimos; Lee, Sanghyeon; Seol, Seung Kwon; Utke, Ivo; van Nisselroy, Cathelijn; Zambelli, Tomaso; Wheeler, Jeffrey M.; Spolenak, Ralph

Advanced Functional Materials 30 (2020)

Many emerging applications in microscale engineering rely on the fabrication of 3D architectures in inorganic materials. Small-scale additive manufacturing (AM) aspires to provide flexible and facile access to these geometries. Yet, the synthesis of device-grade inorganic materials is still a key challenge toward the implementation of AM in microfabrication. Here, a comprehensive overview of the microstructural and mechanical properties of metals fabricated by most state-of-the-art AM methods that offer a spatial resolution ≤10 μm is presented. Standardized sets of samples are studied by cross-sectional electron microscopy, nanoindentation, and microcompression. It is shown that current microscale AM techniques synthesize metals with a wide range of microstructures and elastic and plastic properties, including materials of dense and crystalline microstructure with excellent mechanical properties that compare well to those of thin-film nanocrystalline materials. The large variation in materials’ performance can be related to the individual microstructure, which in turn is coupled to the various physico-chemical principles exploited by the different printing methods. The study provides practical guidelines for users of small-scale additive methods and establishes a baseline for the future optimization of the properties of printed metallic objects—a significant step toward the potential establishment of AM techniques in microfabrication.